forked from OSchip/llvm-project
900 lines
32 KiB
C++
900 lines
32 KiB
C++
//===-- PPCTargetTransformInfo.cpp - PPC specific TTI ---------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "PPCTargetTransformInfo.h"
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#include "llvm/Analysis/CodeMetrics.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/CodeGen/BasicTTIImpl.h"
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#include "llvm/CodeGen/CostTable.h"
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#include "llvm/CodeGen/TargetLowering.h"
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#include "llvm/CodeGen/TargetSchedule.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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using namespace llvm;
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#define DEBUG_TYPE "ppctti"
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static cl::opt<bool> DisablePPCConstHoist("disable-ppc-constant-hoisting",
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cl::desc("disable constant hoisting on PPC"), cl::init(false), cl::Hidden);
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// This is currently only used for the data prefetch pass which is only enabled
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// for BG/Q by default.
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static cl::opt<unsigned>
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CacheLineSize("ppc-loop-prefetch-cache-line", cl::Hidden, cl::init(64),
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cl::desc("The loop prefetch cache line size"));
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static cl::opt<bool>
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EnablePPCColdCC("ppc-enable-coldcc", cl::Hidden, cl::init(false),
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cl::desc("Enable using coldcc calling conv for cold "
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"internal functions"));
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// The latency of mtctr is only justified if there are more than 4
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// comparisons that will be removed as a result.
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static cl::opt<unsigned>
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SmallCTRLoopThreshold("min-ctr-loop-threshold", cl::init(4), cl::Hidden,
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cl::desc("Loops with a constant trip count smaller than "
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"this value will not use the count register."));
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//===----------------------------------------------------------------------===//
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//
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// PPC cost model.
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//
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//===----------------------------------------------------------------------===//
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TargetTransformInfo::PopcntSupportKind
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PPCTTIImpl::getPopcntSupport(unsigned TyWidth) {
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assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
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if (ST->hasPOPCNTD() != PPCSubtarget::POPCNTD_Unavailable && TyWidth <= 64)
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return ST->hasPOPCNTD() == PPCSubtarget::POPCNTD_Slow ?
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TTI::PSK_SlowHardware : TTI::PSK_FastHardware;
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return TTI::PSK_Software;
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}
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int PPCTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty) {
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if (DisablePPCConstHoist)
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return BaseT::getIntImmCost(Imm, Ty);
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assert(Ty->isIntegerTy());
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unsigned BitSize = Ty->getPrimitiveSizeInBits();
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if (BitSize == 0)
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return ~0U;
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if (Imm == 0)
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return TTI::TCC_Free;
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if (Imm.getBitWidth() <= 64) {
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if (isInt<16>(Imm.getSExtValue()))
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return TTI::TCC_Basic;
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if (isInt<32>(Imm.getSExtValue())) {
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// A constant that can be materialized using lis.
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if ((Imm.getZExtValue() & 0xFFFF) == 0)
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return TTI::TCC_Basic;
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return 2 * TTI::TCC_Basic;
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}
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}
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return 4 * TTI::TCC_Basic;
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}
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int PPCTTIImpl::getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
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Type *Ty) {
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if (DisablePPCConstHoist)
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return BaseT::getIntImmCost(IID, Idx, Imm, Ty);
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assert(Ty->isIntegerTy());
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unsigned BitSize = Ty->getPrimitiveSizeInBits();
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if (BitSize == 0)
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return ~0U;
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switch (IID) {
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default:
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return TTI::TCC_Free;
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case Intrinsic::sadd_with_overflow:
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case Intrinsic::uadd_with_overflow:
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case Intrinsic::ssub_with_overflow:
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case Intrinsic::usub_with_overflow:
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if ((Idx == 1) && Imm.getBitWidth() <= 64 && isInt<16>(Imm.getSExtValue()))
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return TTI::TCC_Free;
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break;
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case Intrinsic::experimental_stackmap:
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if ((Idx < 2) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
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return TTI::TCC_Free;
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break;
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case Intrinsic::experimental_patchpoint_void:
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case Intrinsic::experimental_patchpoint_i64:
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if ((Idx < 4) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
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return TTI::TCC_Free;
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break;
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}
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return PPCTTIImpl::getIntImmCost(Imm, Ty);
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}
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int PPCTTIImpl::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
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Type *Ty) {
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if (DisablePPCConstHoist)
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return BaseT::getIntImmCost(Opcode, Idx, Imm, Ty);
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assert(Ty->isIntegerTy());
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unsigned BitSize = Ty->getPrimitiveSizeInBits();
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if (BitSize == 0)
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return ~0U;
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unsigned ImmIdx = ~0U;
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bool ShiftedFree = false, RunFree = false, UnsignedFree = false,
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ZeroFree = false;
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switch (Opcode) {
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default:
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return TTI::TCC_Free;
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case Instruction::GetElementPtr:
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// Always hoist the base address of a GetElementPtr. This prevents the
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// creation of new constants for every base constant that gets constant
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// folded with the offset.
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if (Idx == 0)
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return 2 * TTI::TCC_Basic;
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return TTI::TCC_Free;
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case Instruction::And:
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RunFree = true; // (for the rotate-and-mask instructions)
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LLVM_FALLTHROUGH;
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case Instruction::Add:
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case Instruction::Or:
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case Instruction::Xor:
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ShiftedFree = true;
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LLVM_FALLTHROUGH;
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case Instruction::Sub:
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case Instruction::Mul:
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case Instruction::Shl:
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case Instruction::LShr:
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case Instruction::AShr:
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ImmIdx = 1;
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break;
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case Instruction::ICmp:
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UnsignedFree = true;
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ImmIdx = 1;
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// Zero comparisons can use record-form instructions.
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LLVM_FALLTHROUGH;
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case Instruction::Select:
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ZeroFree = true;
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break;
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case Instruction::PHI:
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case Instruction::Call:
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case Instruction::Ret:
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case Instruction::Load:
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case Instruction::Store:
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break;
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}
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if (ZeroFree && Imm == 0)
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return TTI::TCC_Free;
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if (Idx == ImmIdx && Imm.getBitWidth() <= 64) {
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if (isInt<16>(Imm.getSExtValue()))
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return TTI::TCC_Free;
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if (RunFree) {
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if (Imm.getBitWidth() <= 32 &&
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(isShiftedMask_32(Imm.getZExtValue()) ||
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isShiftedMask_32(~Imm.getZExtValue())))
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return TTI::TCC_Free;
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if (ST->isPPC64() &&
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(isShiftedMask_64(Imm.getZExtValue()) ||
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isShiftedMask_64(~Imm.getZExtValue())))
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return TTI::TCC_Free;
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}
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if (UnsignedFree && isUInt<16>(Imm.getZExtValue()))
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return TTI::TCC_Free;
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if (ShiftedFree && (Imm.getZExtValue() & 0xFFFF) == 0)
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return TTI::TCC_Free;
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}
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return PPCTTIImpl::getIntImmCost(Imm, Ty);
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}
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unsigned PPCTTIImpl::getUserCost(const User *U,
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ArrayRef<const Value *> Operands) {
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if (U->getType()->isVectorTy()) {
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// Instructions that need to be split should cost more.
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std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, U->getType());
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return LT.first * BaseT::getUserCost(U, Operands);
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}
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return BaseT::getUserCost(U, Operands);
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}
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bool PPCTTIImpl::mightUseCTR(BasicBlock *BB,
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TargetLibraryInfo *LibInfo) {
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const PPCTargetMachine &TM = ST->getTargetMachine();
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// Loop through the inline asm constraints and look for something that
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// clobbers ctr.
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auto asmClobbersCTR = [](InlineAsm *IA) {
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InlineAsm::ConstraintInfoVector CIV = IA->ParseConstraints();
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for (unsigned i = 0, ie = CIV.size(); i < ie; ++i) {
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InlineAsm::ConstraintInfo &C = CIV[i];
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if (C.Type != InlineAsm::isInput)
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for (unsigned j = 0, je = C.Codes.size(); j < je; ++j)
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if (StringRef(C.Codes[j]).equals_lower("{ctr}"))
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return true;
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}
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return false;
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};
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// Determining the address of a TLS variable results in a function call in
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// certain TLS models.
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std::function<bool(const Value*)> memAddrUsesCTR =
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[&memAddrUsesCTR, &TM](const Value *MemAddr) -> bool {
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const auto *GV = dyn_cast<GlobalValue>(MemAddr);
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if (!GV) {
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// Recurse to check for constants that refer to TLS global variables.
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if (const auto *CV = dyn_cast<Constant>(MemAddr))
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for (const auto &CO : CV->operands())
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if (memAddrUsesCTR(CO))
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return true;
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return false;
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}
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if (!GV->isThreadLocal())
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return false;
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TLSModel::Model Model = TM.getTLSModel(GV);
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return Model == TLSModel::GeneralDynamic ||
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Model == TLSModel::LocalDynamic;
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};
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auto isLargeIntegerTy = [](bool Is32Bit, Type *Ty) {
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if (IntegerType *ITy = dyn_cast<IntegerType>(Ty))
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return ITy->getBitWidth() > (Is32Bit ? 32U : 64U);
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return false;
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};
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for (BasicBlock::iterator J = BB->begin(), JE = BB->end();
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J != JE; ++J) {
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if (CallInst *CI = dyn_cast<CallInst>(J)) {
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// Inline ASM is okay, unless it clobbers the ctr register.
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if (InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue())) {
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if (asmClobbersCTR(IA))
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return true;
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continue;
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}
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if (Function *F = CI->getCalledFunction()) {
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// Most intrinsics don't become function calls, but some might.
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// sin, cos, exp and log are always calls.
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unsigned Opcode = 0;
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if (F->getIntrinsicID() != Intrinsic::not_intrinsic) {
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switch (F->getIntrinsicID()) {
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default: continue;
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// If we have a call to ppc_is_decremented_ctr_nonzero, or ppc_mtctr
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// we're definitely using CTR.
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case Intrinsic::set_loop_iterations:
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case Intrinsic::loop_decrement:
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return true;
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// VisualStudio defines setjmp as _setjmp
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#if defined(_MSC_VER) && defined(setjmp) && \
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!defined(setjmp_undefined_for_msvc)
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# pragma push_macro("setjmp")
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# undef setjmp
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# define setjmp_undefined_for_msvc
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#endif
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case Intrinsic::setjmp:
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#if defined(_MSC_VER) && defined(setjmp_undefined_for_msvc)
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// let's return it to _setjmp state
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# pragma pop_macro("setjmp")
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# undef setjmp_undefined_for_msvc
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#endif
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case Intrinsic::longjmp:
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// Exclude eh_sjlj_setjmp; we don't need to exclude eh_sjlj_longjmp
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// because, although it does clobber the counter register, the
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// control can't then return to inside the loop unless there is also
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// an eh_sjlj_setjmp.
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case Intrinsic::eh_sjlj_setjmp:
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case Intrinsic::memcpy:
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case Intrinsic::memmove:
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case Intrinsic::memset:
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case Intrinsic::powi:
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case Intrinsic::log:
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case Intrinsic::log2:
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case Intrinsic::log10:
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case Intrinsic::exp:
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case Intrinsic::exp2:
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case Intrinsic::pow:
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case Intrinsic::sin:
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case Intrinsic::cos:
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return true;
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case Intrinsic::copysign:
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if (CI->getArgOperand(0)->getType()->getScalarType()->
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isPPC_FP128Ty())
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return true;
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else
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continue; // ISD::FCOPYSIGN is never a library call.
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case Intrinsic::sqrt: Opcode = ISD::FSQRT; break;
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case Intrinsic::floor: Opcode = ISD::FFLOOR; break;
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case Intrinsic::ceil: Opcode = ISD::FCEIL; break;
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case Intrinsic::trunc: Opcode = ISD::FTRUNC; break;
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case Intrinsic::rint: Opcode = ISD::FRINT; break;
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case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break;
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case Intrinsic::round: Opcode = ISD::FROUND; break;
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case Intrinsic::minnum: Opcode = ISD::FMINNUM; break;
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case Intrinsic::maxnum: Opcode = ISD::FMAXNUM; break;
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case Intrinsic::umul_with_overflow: Opcode = ISD::UMULO; break;
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case Intrinsic::smul_with_overflow: Opcode = ISD::SMULO; break;
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}
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}
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// PowerPC does not use [US]DIVREM or other library calls for
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// operations on regular types which are not otherwise library calls
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// (i.e. soft float or atomics). If adapting for targets that do,
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// additional care is required here.
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LibFunc Func;
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if (!F->hasLocalLinkage() && F->hasName() && LibInfo &&
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LibInfo->getLibFunc(F->getName(), Func) &&
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LibInfo->hasOptimizedCodeGen(Func)) {
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// Non-read-only functions are never treated as intrinsics.
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if (!CI->onlyReadsMemory())
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return true;
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// Conversion happens only for FP calls.
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if (!CI->getArgOperand(0)->getType()->isFloatingPointTy())
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return true;
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switch (Func) {
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default: return true;
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case LibFunc_copysign:
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case LibFunc_copysignf:
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continue; // ISD::FCOPYSIGN is never a library call.
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case LibFunc_copysignl:
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return true;
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case LibFunc_fabs:
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case LibFunc_fabsf:
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case LibFunc_fabsl:
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continue; // ISD::FABS is never a library call.
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case LibFunc_sqrt:
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case LibFunc_sqrtf:
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case LibFunc_sqrtl:
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Opcode = ISD::FSQRT; break;
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case LibFunc_floor:
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case LibFunc_floorf:
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case LibFunc_floorl:
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Opcode = ISD::FFLOOR; break;
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case LibFunc_nearbyint:
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case LibFunc_nearbyintf:
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case LibFunc_nearbyintl:
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Opcode = ISD::FNEARBYINT; break;
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case LibFunc_ceil:
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case LibFunc_ceilf:
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case LibFunc_ceill:
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Opcode = ISD::FCEIL; break;
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case LibFunc_rint:
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case LibFunc_rintf:
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case LibFunc_rintl:
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Opcode = ISD::FRINT; break;
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case LibFunc_round:
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case LibFunc_roundf:
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case LibFunc_roundl:
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Opcode = ISD::FROUND; break;
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case LibFunc_trunc:
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case LibFunc_truncf:
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case LibFunc_truncl:
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Opcode = ISD::FTRUNC; break;
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case LibFunc_fmin:
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case LibFunc_fminf:
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case LibFunc_fminl:
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Opcode = ISD::FMINNUM; break;
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case LibFunc_fmax:
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case LibFunc_fmaxf:
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case LibFunc_fmaxl:
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Opcode = ISD::FMAXNUM; break;
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}
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}
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if (Opcode) {
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EVT EVTy =
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TLI->getValueType(DL, CI->getArgOperand(0)->getType(), true);
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if (EVTy == MVT::Other)
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return true;
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if (TLI->isOperationLegalOrCustom(Opcode, EVTy))
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continue;
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else if (EVTy.isVector() &&
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TLI->isOperationLegalOrCustom(Opcode, EVTy.getScalarType()))
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continue;
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return true;
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}
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}
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return true;
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} else if (isa<BinaryOperator>(J) &&
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J->getType()->getScalarType()->isPPC_FP128Ty()) {
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// Most operations on ppc_f128 values become calls.
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return true;
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} else if (isa<UIToFPInst>(J) || isa<SIToFPInst>(J) ||
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isa<FPToUIInst>(J) || isa<FPToSIInst>(J)) {
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CastInst *CI = cast<CastInst>(J);
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if (CI->getSrcTy()->getScalarType()->isPPC_FP128Ty() ||
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CI->getDestTy()->getScalarType()->isPPC_FP128Ty() ||
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isLargeIntegerTy(!TM.isPPC64(), CI->getSrcTy()->getScalarType()) ||
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isLargeIntegerTy(!TM.isPPC64(), CI->getDestTy()->getScalarType()))
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return true;
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} else if (isLargeIntegerTy(!TM.isPPC64(),
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J->getType()->getScalarType()) &&
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(J->getOpcode() == Instruction::UDiv ||
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J->getOpcode() == Instruction::SDiv ||
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J->getOpcode() == Instruction::URem ||
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J->getOpcode() == Instruction::SRem)) {
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return true;
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} else if (!TM.isPPC64() &&
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isLargeIntegerTy(false, J->getType()->getScalarType()) &&
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(J->getOpcode() == Instruction::Shl ||
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J->getOpcode() == Instruction::AShr ||
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J->getOpcode() == Instruction::LShr)) {
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// Only on PPC32, for 128-bit integers (specifically not 64-bit
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// integers), these might be runtime calls.
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return true;
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} else if (isa<IndirectBrInst>(J) || isa<InvokeInst>(J)) {
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// On PowerPC, indirect jumps use the counter register.
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return true;
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} else if (SwitchInst *SI = dyn_cast<SwitchInst>(J)) {
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if (SI->getNumCases() + 1 >= (unsigned)TLI->getMinimumJumpTableEntries())
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return true;
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}
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// FREM is always a call.
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if (J->getOpcode() == Instruction::FRem)
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return true;
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if (ST->useSoftFloat()) {
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switch(J->getOpcode()) {
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case Instruction::FAdd:
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case Instruction::FSub:
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case Instruction::FMul:
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case Instruction::FDiv:
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case Instruction::FPTrunc:
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case Instruction::FPExt:
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case Instruction::FPToUI:
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case Instruction::FPToSI:
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case Instruction::UIToFP:
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case Instruction::SIToFP:
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case Instruction::FCmp:
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return true;
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}
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}
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for (Value *Operand : J->operands())
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if (memAddrUsesCTR(Operand))
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return true;
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|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool PPCTTIImpl::isHardwareLoopProfitable(Loop *L, ScalarEvolution &SE,
|
|
AssumptionCache &AC,
|
|
TargetLibraryInfo *LibInfo,
|
|
HardwareLoopInfo &HWLoopInfo) {
|
|
const PPCTargetMachine &TM = ST->getTargetMachine();
|
|
TargetSchedModel SchedModel;
|
|
SchedModel.init(ST);
|
|
|
|
// Do not convert small short loops to CTR loop.
|
|
unsigned ConstTripCount = SE.getSmallConstantTripCount(L);
|
|
if (ConstTripCount && ConstTripCount < SmallCTRLoopThreshold) {
|
|
SmallPtrSet<const Value *, 32> EphValues;
|
|
CodeMetrics::collectEphemeralValues(L, &AC, EphValues);
|
|
CodeMetrics Metrics;
|
|
for (BasicBlock *BB : L->blocks())
|
|
Metrics.analyzeBasicBlock(BB, *this, EphValues);
|
|
// 6 is an approximate latency for the mtctr instruction.
|
|
if (Metrics.NumInsts <= (6 * SchedModel.getIssueWidth()))
|
|
return false;
|
|
}
|
|
|
|
// We don't want to spill/restore the counter register, and so we don't
|
|
// want to use the counter register if the loop contains calls.
|
|
for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
|
|
I != IE; ++I)
|
|
if (mightUseCTR(*I, LibInfo))
|
|
return false;
|
|
|
|
SmallVector<BasicBlock*, 4> ExitingBlocks;
|
|
L->getExitingBlocks(ExitingBlocks);
|
|
|
|
// If there is an exit edge known to be frequently taken,
|
|
// we should not transform this loop.
|
|
for (auto &BB : ExitingBlocks) {
|
|
Instruction *TI = BB->getTerminator();
|
|
if (!TI) continue;
|
|
|
|
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
|
|
uint64_t TrueWeight = 0, FalseWeight = 0;
|
|
if (!BI->isConditional() ||
|
|
!BI->extractProfMetadata(TrueWeight, FalseWeight))
|
|
continue;
|
|
|
|
// If the exit path is more frequent than the loop path,
|
|
// we return here without further analysis for this loop.
|
|
bool TrueIsExit = !L->contains(BI->getSuccessor(0));
|
|
if (( TrueIsExit && FalseWeight < TrueWeight) ||
|
|
(!TrueIsExit && FalseWeight > TrueWeight))
|
|
return false;
|
|
}
|
|
}
|
|
|
|
LLVMContext &C = L->getHeader()->getContext();
|
|
HWLoopInfo.CountType = TM.isPPC64() ?
|
|
Type::getInt64Ty(C) : Type::getInt32Ty(C);
|
|
HWLoopInfo.LoopDecrement = ConstantInt::get(HWLoopInfo.CountType, 1);
|
|
return true;
|
|
}
|
|
|
|
void PPCTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
|
|
TTI::UnrollingPreferences &UP) {
|
|
if (ST->getDarwinDirective() == PPC::DIR_A2) {
|
|
// The A2 is in-order with a deep pipeline, and concatenation unrolling
|
|
// helps expose latency-hiding opportunities to the instruction scheduler.
|
|
UP.Partial = UP.Runtime = true;
|
|
|
|
// We unroll a lot on the A2 (hundreds of instructions), and the benefits
|
|
// often outweigh the cost of a division to compute the trip count.
|
|
UP.AllowExpensiveTripCount = true;
|
|
}
|
|
|
|
BaseT::getUnrollingPreferences(L, SE, UP);
|
|
}
|
|
|
|
// This function returns true to allow using coldcc calling convention.
|
|
// Returning true results in coldcc being used for functions which are cold at
|
|
// all call sites when the callers of the functions are not calling any other
|
|
// non coldcc functions.
|
|
bool PPCTTIImpl::useColdCCForColdCall(Function &F) {
|
|
return EnablePPCColdCC;
|
|
}
|
|
|
|
bool PPCTTIImpl::enableAggressiveInterleaving(bool LoopHasReductions) {
|
|
// On the A2, always unroll aggressively. For QPX unaligned loads, we depend
|
|
// on combining the loads generated for consecutive accesses, and failure to
|
|
// do so is particularly expensive. This makes it much more likely (compared
|
|
// to only using concatenation unrolling).
|
|
if (ST->getDarwinDirective() == PPC::DIR_A2)
|
|
return true;
|
|
|
|
return LoopHasReductions;
|
|
}
|
|
|
|
PPCTTIImpl::TTI::MemCmpExpansionOptions
|
|
PPCTTIImpl::enableMemCmpExpansion(bool OptSize, bool IsZeroCmp) const {
|
|
TTI::MemCmpExpansionOptions Options;
|
|
Options.LoadSizes = {8, 4, 2, 1};
|
|
Options.MaxNumLoads = TLI->getMaxExpandSizeMemcmp(OptSize);
|
|
return Options;
|
|
}
|
|
|
|
bool PPCTTIImpl::enableInterleavedAccessVectorization() {
|
|
return true;
|
|
}
|
|
|
|
unsigned PPCTTIImpl::getNumberOfRegisters(bool Vector) {
|
|
if (Vector && !ST->hasAltivec() && !ST->hasQPX())
|
|
return 0;
|
|
return ST->hasVSX() ? 64 : 32;
|
|
}
|
|
|
|
unsigned PPCTTIImpl::getRegisterBitWidth(bool Vector) const {
|
|
if (Vector) {
|
|
if (ST->hasQPX()) return 256;
|
|
if (ST->hasAltivec()) return 128;
|
|
return 0;
|
|
}
|
|
|
|
if (ST->isPPC64())
|
|
return 64;
|
|
return 32;
|
|
|
|
}
|
|
|
|
unsigned PPCTTIImpl::getCacheLineSize() {
|
|
// Check first if the user specified a custom line size.
|
|
if (CacheLineSize.getNumOccurrences() > 0)
|
|
return CacheLineSize;
|
|
|
|
// On P7, P8 or P9 we have a cache line size of 128.
|
|
unsigned Directive = ST->getDarwinDirective();
|
|
if (Directive == PPC::DIR_PWR7 || Directive == PPC::DIR_PWR8 ||
|
|
Directive == PPC::DIR_PWR9)
|
|
return 128;
|
|
|
|
// On other processors return a default of 64 bytes.
|
|
return 64;
|
|
}
|
|
|
|
unsigned PPCTTIImpl::getPrefetchDistance() {
|
|
// This seems like a reasonable default for the BG/Q (this pass is enabled, by
|
|
// default, only on the BG/Q).
|
|
return 300;
|
|
}
|
|
|
|
unsigned PPCTTIImpl::getMaxInterleaveFactor(unsigned VF) {
|
|
unsigned Directive = ST->getDarwinDirective();
|
|
// The 440 has no SIMD support, but floating-point instructions
|
|
// have a 5-cycle latency, so unroll by 5x for latency hiding.
|
|
if (Directive == PPC::DIR_440)
|
|
return 5;
|
|
|
|
// The A2 has no SIMD support, but floating-point instructions
|
|
// have a 6-cycle latency, so unroll by 6x for latency hiding.
|
|
if (Directive == PPC::DIR_A2)
|
|
return 6;
|
|
|
|
// FIXME: For lack of any better information, do no harm...
|
|
if (Directive == PPC::DIR_E500mc || Directive == PPC::DIR_E5500)
|
|
return 1;
|
|
|
|
// For P7 and P8, floating-point instructions have a 6-cycle latency and
|
|
// there are two execution units, so unroll by 12x for latency hiding.
|
|
// FIXME: the same for P9 as previous gen until POWER9 scheduling is ready
|
|
if (Directive == PPC::DIR_PWR7 || Directive == PPC::DIR_PWR8 ||
|
|
Directive == PPC::DIR_PWR9)
|
|
return 12;
|
|
|
|
// For most things, modern systems have two execution units (and
|
|
// out-of-order execution).
|
|
return 2;
|
|
}
|
|
|
|
// Adjust the cost of vector instructions on targets which there is overlap
|
|
// between the vector and scalar units, thereby reducing the overall throughput
|
|
// of vector code wrt. scalar code.
|
|
int PPCTTIImpl::vectorCostAdjustment(int Cost, unsigned Opcode, Type *Ty1,
|
|
Type *Ty2) {
|
|
if (!ST->vectorsUseTwoUnits() || !Ty1->isVectorTy())
|
|
return Cost;
|
|
|
|
std::pair<int, MVT> LT1 = TLI->getTypeLegalizationCost(DL, Ty1);
|
|
// If type legalization involves splitting the vector, we don't want to
|
|
// double the cost at every step - only the last step.
|
|
if (LT1.first != 1 || !LT1.second.isVector())
|
|
return Cost;
|
|
|
|
int ISD = TLI->InstructionOpcodeToISD(Opcode);
|
|
if (TLI->isOperationExpand(ISD, LT1.second))
|
|
return Cost;
|
|
|
|
if (Ty2) {
|
|
std::pair<int, MVT> LT2 = TLI->getTypeLegalizationCost(DL, Ty2);
|
|
if (LT2.first != 1 || !LT2.second.isVector())
|
|
return Cost;
|
|
}
|
|
|
|
return Cost * 2;
|
|
}
|
|
|
|
int PPCTTIImpl::getArithmeticInstrCost(
|
|
unsigned Opcode, Type *Ty, TTI::OperandValueKind Op1Info,
|
|
TTI::OperandValueKind Op2Info, TTI::OperandValueProperties Opd1PropInfo,
|
|
TTI::OperandValueProperties Opd2PropInfo, ArrayRef<const Value *> Args) {
|
|
assert(TLI->InstructionOpcodeToISD(Opcode) && "Invalid opcode");
|
|
|
|
// Fallback to the default implementation.
|
|
int Cost = BaseT::getArithmeticInstrCost(Opcode, Ty, Op1Info, Op2Info,
|
|
Opd1PropInfo, Opd2PropInfo);
|
|
return vectorCostAdjustment(Cost, Opcode, Ty, nullptr);
|
|
}
|
|
|
|
int PPCTTIImpl::getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
|
|
Type *SubTp) {
|
|
// Legalize the type.
|
|
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Tp);
|
|
|
|
// PPC, for both Altivec/VSX and QPX, support cheap arbitrary permutations
|
|
// (at least in the sense that there need only be one non-loop-invariant
|
|
// instruction). We need one such shuffle instruction for each actual
|
|
// register (this is not true for arbitrary shuffles, but is true for the
|
|
// structured types of shuffles covered by TTI::ShuffleKind).
|
|
return vectorCostAdjustment(LT.first, Instruction::ShuffleVector, Tp,
|
|
nullptr);
|
|
}
|
|
|
|
int PPCTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
|
|
const Instruction *I) {
|
|
assert(TLI->InstructionOpcodeToISD(Opcode) && "Invalid opcode");
|
|
|
|
int Cost = BaseT::getCastInstrCost(Opcode, Dst, Src);
|
|
return vectorCostAdjustment(Cost, Opcode, Dst, Src);
|
|
}
|
|
|
|
int PPCTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
|
|
const Instruction *I) {
|
|
int Cost = BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, I);
|
|
return vectorCostAdjustment(Cost, Opcode, ValTy, nullptr);
|
|
}
|
|
|
|
int PPCTTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index) {
|
|
assert(Val->isVectorTy() && "This must be a vector type");
|
|
|
|
int ISD = TLI->InstructionOpcodeToISD(Opcode);
|
|
assert(ISD && "Invalid opcode");
|
|
|
|
int Cost = BaseT::getVectorInstrCost(Opcode, Val, Index);
|
|
Cost = vectorCostAdjustment(Cost, Opcode, Val, nullptr);
|
|
|
|
if (ST->hasVSX() && Val->getScalarType()->isDoubleTy()) {
|
|
// Double-precision scalars are already located in index #0 (or #1 if LE).
|
|
if (ISD == ISD::EXTRACT_VECTOR_ELT &&
|
|
Index == (ST->isLittleEndian() ? 1 : 0))
|
|
return 0;
|
|
|
|
return Cost;
|
|
|
|
} else if (ST->hasQPX() && Val->getScalarType()->isFloatingPointTy()) {
|
|
// Floating point scalars are already located in index #0.
|
|
if (Index == 0)
|
|
return 0;
|
|
|
|
return Cost;
|
|
}
|
|
|
|
// Estimated cost of a load-hit-store delay. This was obtained
|
|
// experimentally as a minimum needed to prevent unprofitable
|
|
// vectorization for the paq8p benchmark. It may need to be
|
|
// raised further if other unprofitable cases remain.
|
|
unsigned LHSPenalty = 2;
|
|
if (ISD == ISD::INSERT_VECTOR_ELT)
|
|
LHSPenalty += 7;
|
|
|
|
// Vector element insert/extract with Altivec is very expensive,
|
|
// because they require store and reload with the attendant
|
|
// processor stall for load-hit-store. Until VSX is available,
|
|
// these need to be estimated as very costly.
|
|
if (ISD == ISD::EXTRACT_VECTOR_ELT ||
|
|
ISD == ISD::INSERT_VECTOR_ELT)
|
|
return LHSPenalty + Cost;
|
|
|
|
return Cost;
|
|
}
|
|
|
|
int PPCTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
|
|
unsigned AddressSpace, const Instruction *I) {
|
|
// Legalize the type.
|
|
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, Src);
|
|
assert((Opcode == Instruction::Load || Opcode == Instruction::Store) &&
|
|
"Invalid Opcode");
|
|
|
|
int Cost = BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace);
|
|
Cost = vectorCostAdjustment(Cost, Opcode, Src, nullptr);
|
|
|
|
bool IsAltivecType = ST->hasAltivec() &&
|
|
(LT.second == MVT::v16i8 || LT.second == MVT::v8i16 ||
|
|
LT.second == MVT::v4i32 || LT.second == MVT::v4f32);
|
|
bool IsVSXType = ST->hasVSX() &&
|
|
(LT.second == MVT::v2f64 || LT.second == MVT::v2i64);
|
|
bool IsQPXType = ST->hasQPX() &&
|
|
(LT.second == MVT::v4f64 || LT.second == MVT::v4f32);
|
|
|
|
// VSX has 32b/64b load instructions. Legalization can handle loading of
|
|
// 32b/64b to VSR correctly and cheaply. But BaseT::getMemoryOpCost and
|
|
// PPCTargetLowering can't compute the cost appropriately. So here we
|
|
// explicitly check this case.
|
|
unsigned MemBytes = Src->getPrimitiveSizeInBits();
|
|
if (Opcode == Instruction::Load && ST->hasVSX() && IsAltivecType &&
|
|
(MemBytes == 64 || (ST->hasP8Vector() && MemBytes == 32)))
|
|
return 1;
|
|
|
|
// Aligned loads and stores are easy.
|
|
unsigned SrcBytes = LT.second.getStoreSize();
|
|
if (!SrcBytes || !Alignment || Alignment >= SrcBytes)
|
|
return Cost;
|
|
|
|
// If we can use the permutation-based load sequence, then this is also
|
|
// relatively cheap (not counting loop-invariant instructions): one load plus
|
|
// one permute (the last load in a series has extra cost, but we're
|
|
// neglecting that here). Note that on the P7, we could do unaligned loads
|
|
// for Altivec types using the VSX instructions, but that's more expensive
|
|
// than using the permutation-based load sequence. On the P8, that's no
|
|
// longer true.
|
|
if (Opcode == Instruction::Load &&
|
|
((!ST->hasP8Vector() && IsAltivecType) || IsQPXType) &&
|
|
Alignment >= LT.second.getScalarType().getStoreSize())
|
|
return Cost + LT.first; // Add the cost of the permutations.
|
|
|
|
// For VSX, we can do unaligned loads and stores on Altivec/VSX types. On the
|
|
// P7, unaligned vector loads are more expensive than the permutation-based
|
|
// load sequence, so that might be used instead, but regardless, the net cost
|
|
// is about the same (not counting loop-invariant instructions).
|
|
if (IsVSXType || (ST->hasVSX() && IsAltivecType))
|
|
return Cost;
|
|
|
|
// Newer PPC supports unaligned memory access.
|
|
if (TLI->allowsMisalignedMemoryAccesses(LT.second, 0))
|
|
return Cost;
|
|
|
|
// PPC in general does not support unaligned loads and stores. They'll need
|
|
// to be decomposed based on the alignment factor.
|
|
|
|
// Add the cost of each scalar load or store.
|
|
Cost += LT.first*(SrcBytes/Alignment-1);
|
|
|
|
// For a vector type, there is also scalarization overhead (only for
|
|
// stores, loads are expanded using the vector-load + permutation sequence,
|
|
// which is much less expensive).
|
|
if (Src->isVectorTy() && Opcode == Instruction::Store)
|
|
for (int i = 0, e = Src->getVectorNumElements(); i < e; ++i)
|
|
Cost += getVectorInstrCost(Instruction::ExtractElement, Src, i);
|
|
|
|
return Cost;
|
|
}
|
|
|
|
int PPCTTIImpl::getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy,
|
|
unsigned Factor,
|
|
ArrayRef<unsigned> Indices,
|
|
unsigned Alignment,
|
|
unsigned AddressSpace,
|
|
bool UseMaskForCond,
|
|
bool UseMaskForGaps) {
|
|
if (UseMaskForCond || UseMaskForGaps)
|
|
return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices,
|
|
Alignment, AddressSpace,
|
|
UseMaskForCond, UseMaskForGaps);
|
|
|
|
assert(isa<VectorType>(VecTy) &&
|
|
"Expect a vector type for interleaved memory op");
|
|
|
|
// Legalize the type.
|
|
std::pair<int, MVT> LT = TLI->getTypeLegalizationCost(DL, VecTy);
|
|
|
|
// Firstly, the cost of load/store operation.
|
|
int Cost = getMemoryOpCost(Opcode, VecTy, Alignment, AddressSpace);
|
|
|
|
// PPC, for both Altivec/VSX and QPX, support cheap arbitrary permutations
|
|
// (at least in the sense that there need only be one non-loop-invariant
|
|
// instruction). For each result vector, we need one shuffle per incoming
|
|
// vector (except that the first shuffle can take two incoming vectors
|
|
// because it does not need to take itself).
|
|
Cost += Factor*(LT.first-1);
|
|
|
|
return Cost;
|
|
}
|
|
|
|
bool PPCTTIImpl::canSaveCmp(Loop *L, BranchInst **BI, ScalarEvolution *SE,
|
|
LoopInfo *LI, DominatorTree *DT,
|
|
AssumptionCache *AC, TargetLibraryInfo *LibInfo) {
|
|
// Process nested loops first.
|
|
for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
|
|
if (canSaveCmp(*I, BI, SE, LI, DT, AC, LibInfo))
|
|
return false; // Stop search.
|
|
|
|
HardwareLoopInfo HWLoopInfo(L);
|
|
|
|
if (!HWLoopInfo.canAnalyze(*LI))
|
|
return false;
|
|
|
|
if (!isHardwareLoopProfitable(L, *SE, *AC, LibInfo, HWLoopInfo))
|
|
return false;
|
|
|
|
if (!HWLoopInfo.isHardwareLoopCandidate(*SE, *LI, *DT))
|
|
return false;
|
|
|
|
*BI = HWLoopInfo.ExitBranch;
|
|
return true;
|
|
}
|